1. Field of the Invention
This invention relates to a hammer mill for crushing ore and the like materials, being of a type which comprises a substantially cylindrical case clad with armor plates on its inside, and a rotor journalled on the case and carrying a plurality of hammers, as well as anchor means for holding each hammer on the rotor at a position to confront the armor plates.
2. Description of the Related Art
Hammer mills for crushing ore and the like materials require that the hammers be secured to the rotor appropriately to enable the hammers to perform their function, which is one of striking the material to be crushed and throwing it with great force against the armor plates. Thus, the material will rebound in pieces from the armor plates, to be once again thrown by the hammers against the armor plates, and this until the material fragment size becomes so small as to drop through a gap or gaps between the rotor and armor plates out of the mill.
In view of the markedly abrasive action exerted by ore materials, the hammers are liable to wear out at a fast rate, and must be replaced with new ones at fairly frequent intervels.
Mills are known wherein the rotor is provided with pegs and the hammers are U-shaped, so that they can be mounted to the rotor each astride a respective one of the pegs. This prior design has the advantage that a hammer can be removed from the rotor more readily, but is deficient as relates to providing a secure attachment of the hammer to the rotor. In fact, with the mill in operation, relative movements occur between the hammer and the rotor leading to mutual impacts which may be substantial and result in the contacting surfaces becoming damaged, and in the extreme, in mechanical failure of either the hammers of the rotor.
Also known are mills in which each hammer has a slotted portion fitting in a corresponding seat formed on the rotor. This prior design does provide for a strong attachment of the hammer to the rotor, but still has a serious drawback which shows up each time that the hammers require to be replaced. Due to the ore powder present within the mill, which gets into the interstices between the mating slot profiles on the hammer and rotor, a "weld" fillet forms between the hammer and the rotor which makes the hammer removal from the rotor a laborious and time-consuming operation, with the net result of extending the mill downtime.